Interesting choice, I always thought oak trees didn't like urban pollution.
Oaks are medium tolerant, but moreso than the City allows for.
Off-the-top of my head; I'd probably rate White Birch as the least urban tolerant native, though there are probably others worthy of mention.
When it comes to salt, Sugar Maples don't get along well with it at all.
At the other extreme are Silver Maples, Honey Locusts, Basswoods and White Spruce as being among the most urban-tolerant species.
Is it the relatively small cells they're confined to that's the bigger issue? Hopefully they do well as I agree that the city doesn't plant them enough.
Soil volume is a big issue, yes. Oaks may grow in less conditions, but their size, and longevity will be immeasurably improved by higher soil volumes, and other condition improvements (open soil/irrigation/companion plantings, and adequate sun).
Oaks are a full-sun species; notwithstanding Yonge being a N-S road, the shadows of the buildings to the south make this less sunny than would be best for oaks as well.
These planter boxes, on the south side of Charles St. Green P were originally oaks..........
None survived, despite decent sunlight levels.
By contrast, look at this beauty in all her fall glory over on St. George St., just north of Hoskin:
Notice the much larger soil volume, a planter shared with a compatible tree, a high ledge that all but eliminates salt penetration from the sidewalk, relatively little root compaction, the bike lane is also a salt buffer (much less spray than cars would generate next to the curb)
Also, lots of sun!